Sea monkeys eat algae. Sea monkeys are a variety of brine shrimp, and they are found in salty lakes, such as the Great Salt Lake.
The Great Salt Lake is incredibly salty, and the only two living things that can survive in this harsh environment are sea monkeys and their food source, algae. An adult sea monkey only grows to be about half an inch long. A sea monkey's eggs are very hardy, and if the eggs happen to dry out because of drought or another phenomenon, the eggs can still hatch once they are exposed to saltwater, even years later.